Getting Started with MySQL

First apply the gradle plugin in your project.

KotlinGroovy

plugins {
  id("app.cash.sqldelight") version "2.0.0-alpha05"
}

repositories {
  google()
  mavenCentral()
}

sqldelight {
  databases {
    create("Database") {
      packageName.set("com.example")
      dialect = "app.cash.sqldeight:mysql-dialect:2.0.0-alpha05"
    }
  }
}

plugins {
  id "app.cash.sqldelight" version "2.0.0-alpha05"
}

repositories {
  google()
  mavenCentral()
}

sqldelight {
  databases {
    Database { // This will be the name of the generated database class.
      packageName = "com.example"
      dialect = "app.cash.sqldeight:mysql-dialect:2.0.0-alpha05"
    }
  }
}

SQLDelight needs to know the schema of your database. There are typically two approaches to setting up your database's schema. The "Fresh Schema" approach assumes that you are starting with an empty database, and that all the statements necessary to bring it to the desired state will be applied all at once. The "Migration Schema" approach on the other hand assumes that you already have a database and schema set up (e.g. an existing production database), and that you'll progressively apply migrations over time to update your database's schema.

In SQLDelight, these approaches translate to either writing your table definitions in .sq files for a "Fresh Schema", or by writing migration statements in .sqm files for a "Migration Schema". In both cases, your SQL queries will be written in .sq files (as shown here).

Fresh Schema

Put your SQL statements in a .sq file under src/main/sqldelight. Typically the first statement in the SQL file creates a table.

-- src/main/sqldelight/com/example/sqldelight/hockey/data/Player.sq

CREATE TABLE hockeyPlayer (
  player_number INTEGER PRIMARY KEY NOT NULL,
  full_name TEXT NOT NULL
);

CREATE INDEX hockeyPlayer_full_name ON hockeyPlayer(full_name);

INSERT INTO hockeyPlayer (player_number, full_name)
VALUES (15, 'Ryan Getzlaf');

In the same .sq files you can start placing your sql statements to be executed at runtime.

Migration Schema

First, configure gradle to use migrations to assemble the schema:

KotlinGroovy

sqldelight {
  databases {
    create("Database") {
      ...
      sourceFolders = listOf("sqldelight")
      deriveSchemaFromMigrations = true
    }
  }
}

sqldelight {
  databases {
    Database {
      ...
      sourceFolders = ["sqldelight"]
      deriveSchemaFromMigrations = true
    }
  }
}

Migration files have the extension .sqm, and must have a number in their file name indicating what order the migration file runs in. For example, given this hierarchy:

src
`-- main
    `-- sqldelight
        |-- v1__backend.sqm
        `-- v2__backend.sqm

SQLDelight will create the schema by applying v1__backend.sqm and then v2__backend.sqm. Place your normal SQL CREATE/ALTER statements in these files. If another service reads from your migrations files (like flyway), make sure to read the info on migrations and how to output valid SQL.

Typesafe SQL

Before you're able to execute SQL statements at runtime, you need to create a SqlDriver to connect to your database. The easiest way is off of a DataSource that you would get from hikari or other connection managers.

KotlinGroovy

dependencies {
  implementation("app.cash.sqldelight:jdbc-driver:2.0.0-alpha05")
}

dependencies {
  implementation "app.cash.sqldelight:jdbc-driver:2.0.0-alpha05"
}

val driver: SqlDriver = dataSource.asJdbcDriver()

Regardless of if you specify the schema as fresh create table statements or through migrations, runtime SQL goes in .sq files.

SQL statements inside a .sq file can be labeled to have a typesafe function generated for them available at runtime.

selectAll:
SELECT *
FROM hockeyPlayer;

insert:
INSERT INTO hockeyPlayer(player_number, full_name)
VALUES (?, ?);

insertFullPlayerObject:
INSERT INTO hockeyPlayer(player_number, full_name)
VALUES ?;

Files with labeled statements in them will have a queries file generated from them that matches the .sq file name - putting the above sql into Player.sq generates PlayerQueries.kt. To get a reference to PlayerQueries you need to wrap the driver we made above:

// In reality the database and driver above should be created a single time
// and passed around using your favourite dependency injection/service
// locator/singleton pattern.
val database = Database(driver)

val playerQueries: PlayerQueries = database.playerQueries

println(playerQueries.selectAll().executeAsList())
// Prints [HockeyPlayer(15, "Ryan Getzlaf")]

playerQueries.insert(player_number = 10, full_name = "Corey Perry")
println(playerQueries.selectAll().executeAsList())
// Prints [HockeyPlayer(15, "Ryan Getzlaf"), HockeyPlayer(10, "Corey Perry")]

val player = HockeyPlayer(10, "Ronald McDonald")
playerQueries.insertFullPlayerObject(player)

And that's it! Check out the other pages on the sidebar for other functionality.